Download Orion 80-A Telescope User Manual

INSTRUCTION MANUAL
Orion®
ShortTube™ 80-A
80mm Rich-Field Refracting Telescope
#9947
Customer Support (800) 676-1343
E-mail: [email protected]
Corporate Offices (831) 763-7000
Providing Exceptional Consumer Optical Products Since 1975
P.O. Box 1815, Santa Cruz, CA 95061
IN 305 Rev. A 02/07
Welcome to a new world of adventure! Your Orion ShortTube 80-A is a fine-quality instrument designed for both daytime terrestrial viewing and nighttime stargazing. Compact, portable, and easy to use, this versatile scope will provide many hours of
enjoyment for the whole family.
These instructions will help you set up and properly use and care for your telescope. Please read them over thoroughly before
getting started.
Tube rings
Finder scope
Finder scope bracket
Dew/Glare
shield
Eyepiece
(20mm)
Star diagonal
Dovetail tube ring
mounting plate
Focus wheels
Figure 1. The ShortTube 80-A refractor.
Parts List
WARNING: Never look at the sun with your telescope
(or even with just your eyes) without a professionally
made solar filter. Permanent eye damage or blindness
could result. Young children should use this telescope
only with adult supervision.
Avoid using the type of solar filter that screws into an
eyepiece. They are susceptible to cracking under the
intense heat that builds up near the focus point, and
could cause severe retinal damage. Use only the type of
solar filter that covers the front of the telescope. Be sure
also to cover the front of the finder scope with aluminum
foil or another opaque material to prevent physical damage to the internal components of the scope itself as well
as to your eyes.
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Qty.
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Description
Optical tube assembly
20mm Expanse™ 1.25" eyepiece (20x)
1
9mm Expanse™ 1.25" eyepiece (44x)
1
90° Mirror star diagonal, 1.25"
1
8x40 Finder scope
1
Finderscope bracket with O-ring
1
Dovetail tube ring mounting plate
2
Tube rings
2
Tube ring mounting hardware screws
1
Objective lens cap
Alignment thumbscrews
Focus
lock ring
tighten the two black nylon screws a couple of turns each to
secure the finder scope in place. Secure the bracket to the
dovetail mount on the optical tube with the knurled thumbscrew on the dovetail mount.
Tensioner
Figure 2a. The 8x40 finder scope and bracket
1
Soft carry case
1
Hex key (5mm)
Note: The following instructions describe the ShortTube
80-A. If you have purchased the ShortTube 80 Optical Tube
Assembly only, there will be many accessories described
that are not included with your telescope. All of the
described accessories are available from Orion Telescopes
& Binoculars. Contact our Customer Service Department at
800-676-1343 or visit our website at OrionTelescopes.com
for details.
Getting Started
The ShortTube 80-A comes nearly fully assembled from the
factory. The telescope’s optics have been installed and collimated, so you should not have to make any adjustments to
them. Open the box and inspect the contents to make sure
all of the items in the parts list are present.
Please keep the original shipping box. In the unlikely event
you should need to ship the telescope back to Orion for warranty repair service, you should use the original packaging.
The box also makes a very good container for storing the
telescope when it is not in use.
Installing the Finder Scope
To place the finder scope in the finder scope bracket (Figure
2a.), first unthread the two black nylon thumbscrews until
the screw ends are flush with the inside diameter of the
bracket. Place the O-ring that comes on the base of the
bracket over the body of the finder scope until it seats into
the slot on the middle of the finder scope. Slide the eyepiece end (narrow end) of the finder scope into the end of
the bracket’s cylinder opposite the adjustment screws while
pulling the chrome, spring-loaded tensioner on the bracket
with your fingers (Figure 2b.) Push the finder scope through
the bracket until the O-ring seats just inside the front opening of the bracket’s cylinder. Now, release the tensioner and
Figure 2b. Inserting the finder scope into the finder scope bracket.
Installing the Diagonal and Eyepiece
Insert the star diagonal into the focuser drawtube and
secure it with the knurled thumbscrew on the drawtube.
Then insert the 20mm Expanse™ eyepiece into the diagonal
and secure it in place with the thumbscrews on the diagonal.
(Always loosen the thumbscrews before rotating or removing the diagonal or an eyepiece.)
Mounting the Telescope
The ShortTube 80-A can be mounted on Orion equatorial
mounts using the included tube rings and dovetail mounting
plate. Attach the tube rings to the dovetail mounting plate with
the included socket-head cap screws. Insert the socket-head
cap screws through the holes in the plate and thread them into
the base of the tube rings (Figure 2c). Place the optical tube
into the open rings. Close the rings, and use the silver clamping knob on each tube ring to secure the telescope. Now you
are ready to attach the telescope to the equatorial mount.
Tube ring
clamping knobs
Dovetail
mounting
plate
Socket-head
cap screw
5mm Hex key
Figure 2c. Attaching the dovetail mounting plate.
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The dovetail mounting plate now connected to the
ShortTube 80-A connects to the equatorial mount’s dovetail
holder. The dovetail holder has two securing knobs to keep
the dovetail plate securely in place. Be sure to loosen these
two knobs prior to attaching the telescope. While grasping
the telescope firmly, place the dovetail mounting plate into
the mount’s dovetail holder and tighten the clamping knobs
to secure the optical tube.
An equatorial mount is desirable for astronomical viewing
as it allows easy manual and/or motorized electronic tracking of celestial objects as the Earth rotates. Setting circles
on equatorial mounts also enable you to locate objects by
their celestial coordinates (right ascension and declination), which can be found in many observing books and star
atlases.
Note: If you are using an Orion EQ-1 or EQ-2 equatorial
mount, the dovetail mounting plate is not needed for attaching the telescope. Simply mount the telescope to your EQ-1
or EQ-2 mount by attaching the tube rings directly to the
mount head and then placing the telescope into the tube
rings. Be sure to tighten the silver tube ring clamping knobs
to secure the telescope.
The ShortTube 80-A can also be easily mounted on altazimuth mounts like the Orion VersaGo which utilizes a dovetail holder like Orion equatorial mounts. Follow the previous
directions to couple the telescope to the mounting plate
with the tube rings, and to attach the mounting plate to the
VersaGo mount’s dovetail holder.
Alternatively, the ShortTube 80-A can be mounted on any
standard camera tripod that has a 1⁄4"-20 stud. As described
previously, attach the included tube rings to the dovetail
mounting plate using the included hardware and then place
the optical tube into the rings. Be sure to tighten the silver
clamping knob on each tube ring to secure the telescope.
The camera tripod’s 1⁄4"-20 stud will thread directly into the
threaded holes on the bottom of the dovetail mounting plate.
Focusing
The ShortTube 80-A is equipped with a precision rackand-pinion focuser. When you first look in the eyepiece, the
image you see may be fuzzy, or out of focus. If so, gently
turn one of the focusing wheels with your fingers until the
image becomes sharp. You will have to readjust the focus
when aiming at subjects of varying distances, or after
changing eyepieces. Make sure the focus lock thumbscrew
is loosened before focusing. After focusing, you can tighten
it to lock the telescope’s focus into place.
Note: The image in the telescope will appear reversed leftto-right. This is normal for astronomical telescopes that utilize a star diagonal. The finder scope view will also appear
rotated 180° (Figure 2d).
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Naked-eye view
View through the ShortTube 80-A
View through finder scope
Figure 2d. Images through the ShortTube 80-A with its star
diagonal in place will be reversed from left-to-right. Images through
the finder scope will appear upside-down and backwards (rotated
180°).
Do You Wear Eyeglasses?
If you wear eyeglasses, you may be able to keep them on
while you observe, if your eyepieces have enough “eye
relief” to allow you to see the whole field of view. You can
find out by looking through the eyepiece first with your
glasses on and then with them off, and see if the glasses
restrict the view to only a portion of the full field. If they do,
you can easily observe with your glasses off by just refocusing the telescope the needed amount.
Aligning the Finder Scope
The ShortTube 80-A comes with a 8x40 achromatic finder
scope. (The 8x means eight-times magnification, and the
40 indicates a 40mm aperture.) The finder scope makes it
easier to locate the subject you want to observe in the telescope, because the finder scope has a much wider field of
view.
Before you use the finder scope, it must be precisely aligned
with the telescope, so they both point to exactly the same
spot. Alignment is easiest to do in daylight, rather than at
night under the stars. First, insert the lowest-power (20mm)
eyepiece into the main telescope’s focuser. Then point the
telescope at a discrete object such as the top of a telephone
pole or a street sign that is at least a quarter-mile away.
Move the telescope so the target object appears in the very
center of the field of view when you look into the eyepiece.
Now look through the finder scope. Is the object centered
in the finder scope’s field of view, i.e., on the crosshairs?
If not, hopefully it will be visible somewhere in the field of
view, so only fine adjustment of the two black nylon alignment screws will be needed. Otherwise you’ll have to make
coarser adjustments to the alignment screws to redirect the
aim of the finder scope.
Use the two alignment screws to center the object on the
crosshairs of the finder scope. Then look again into the main
telescope’s eyepiece and see if it is still centered there as
well. If it isn’t, repeat the entire process, making sure not to
move the main telescope while adjusting the alignment of
the finder scope.
Finder scopes can come out of alignment during transport of
the telescope, so check the alignment before each observing session.
Focusing the Finder Scope
If, when looking through the finder scope, you notice that
the images appear somewhat out of focus, you will need to
refocus the finder scope for your eyes. First loosen the lock
ring located behind the objective lens cell on the body of the
finder scope (see Figure 2a). Back the lock ring off by a few
turns, for now. Refocus the finder scope on a distant object
by threading the objective lens cell in or out of the finder
scope body. Precise focusing will be achieved by focusing the
finder scope on a bright star. Once the image appears sharp,
retighten the lock ring behind the objective lens cell. The finder scope’s focus should not need to be adjusted again.
Astronomical Viewing
The ShortTube 80-A excels for astronomical observation. Its
unobstructed 80mm aperture and short 400mm focal length
(f/5) provide bright, expansive views of star fields and celestial objects residing within our solar system and beyond.
Once the Sun sets, there are literally thousands of objects in
the night sky that can be inspected more closely. For astronomical usage, we’ve included a 90° mirror star diagonal.
The viewing angle provided by a star diagonal is comfortable
for looking up. Keep in mind when using a star diagonal, the
image in the eyepiece will appear backwards (inverted leftto-right).
For casual stargazing, an altazimuth mount mount will do
the job just fine. But an equatorial mount is designed to
make it easier to manually “track” the motion of celestial
objects (due to the rotation of the Earth) with just one slowmotion cable. Furthermore, with an equatorial mount you
can add an optional motor drive to track the stars automatically—a great convenience.
When selecting a location for nighttime stargazing, make
it as far away from city lights as possible. Light-polluted
skies greatly reduce what can be seen with the telescope.
Also, give your eyes at least 20 minutes to dark-adapt to the
night sky. You’ll be surprised at how many more stars you
will see! Use a red flashlight to see what you’re doing at the
telescope, or to read star charts. Red light will not spoil your
dark-adapted night vision as readily as white light will.
To find celestial objects with your telescope, you first need
to become reasonably familiar with the night sky. Unless you
know how to recognize the constellation Orion, for instance,
you won’t have much luck locating the Orion Nebula. A
simple planisphere, or star wheel, can be a valuable tool for
learning the constellations and seeing which ones are visible in the sky on a given night.
A good star chart or atlas can come in handy for helping
locate interesting objects among the dizzying multitude
of stars overhead. Except for the Moon and the brighter
planets, it is pretty time-consuming and frustrating to hunt
for objects randomly, without knowing where to look. It is
best to have specific targets in mind before you begin looking through the eyepiece.
A. The Moon
The Moon, with its rocky, cratered surface, is one of the
easiest and most interesting subjects to observe with your
telescope. The myriad craters, rilles, and jagged mountain formations offer endless fascination. The best time to
observe the Moon is during a partial phase, that is, when
the Moon is not full. During partial phases, shadows cast by
crater walls and mountain peaks along the border between
the dark and light portions of the lunar disk highlight the
surface relief. A full Moon is too bright and devoid of surface
shadows to yield a pleasing view. Try using a Moon filter to
dim the Moon when it is too bright; it simply threads onto the
bottom of the eyepiece.
B. The Sun
You can change your nighttime telescope into a daytime Sun
viewer by installing an optional full-aperture solar filter over
the front opening of the ShortTube 80-A. The primary attraction is sunspots, which change shape, appearance, and location daily. Sunspots are directly related to magnetic activity in
the Sun. Many observers like to make drawings of sunspots
to monitor how the Sun is changing from day to day.
Important Note: Do not look at the Sun with any optical
instrument without a professionally made solar filter, or permanent eye damage could result. Also, remember to cover
or remove the finder scope.
C. The Planets
The planets don’t stay put like stars do (planets don’t have
fixed R.A. and Dec. coordinates), so you will have to refer to
Sky Calendar at our website, www.OrionTelescope.com, or
to charts published monthly in Astronomy,
Astronomy Sky & Telescope,
or other astronomy references to locate them. Venus, Mars,
Jupiter, and Saturn are the brightest objects in the sky after
the Sun and the Moon. All four of these planets are not normally visible in the sky at one time, but chances are one or
two of them will be.
D. Stars
Stars will appear like twinkling points of light in the telescope. Even the largest telescopes cannot magnify stars
to appear as anything more than points of light! You can,
however, enjoy the different colors of the stars and locate
many pretty double and multiple stars. The famous “DoubleDouble” in the constellation Lyra and the gorgeous two-color
double star Albireo in Cygnus are favorites. Defocusing the
image of a star slightly can help bring out its color.
E. Deep-Sky Objects
Under dark skies, you can observe a number of brighter
deep-sky objects with your ShortTube 80-A, including gaseous nebulas, open and globular star clusters, and the
brighter galaxies. Most deep-sky objects are very faint, so it
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is important that you find an observing site well away from
light pollution. Take plenty of time to let your eyes adjust
to the darkness. Don’t expect these objects to appear like
the photographs you see in books and magazines; most
will look like dim gray “ghosts.” (Our eyes are not sensitive
enough to see color in deep-sky objects except in few of the
brightest ones.) But as you become more experienced and
your observing skills improve, you will be able to coax out
more and more intricate details.
Terrestrial Viewing
Many people enjoy using their telescope to view objects
such as boats, birds and wildlife. The ShortTube 80-A is an
excellent instrument for observing during the daylight hours.
For terrestrial applications, we recommend mounting the
ShortTube 80-A on an altazimuth-style telescope mount
or camera tripod, which allow simple vertical (altitude) and
horizontal (azimuth) motions. We also recommend using a
45° correct-image prism diagonal instead of the supplied
star diagonal. A correct-image prism diagonal is designed
for daytime use and yields a properly oriented view (same
as the naked eye).
Calculating Magnification
(Power)
It is desirable to have a range of eyepieces of different focal
lengths, to allow viewing over a range of magnifications. To
calculate the magnification, or power, of a telescope, simply
divide the focal length of the telescope by the focal length of
the eyepiece:
Telescope F.L. ÷ Eyepiece F.L.=Magnification
For example, the ShortTube 80-A, which has a focal length
of 400mm, used in combination with the supplied 20mm
eyepiece, yields a magnification of
400 ÷ 20 = 20x.
Every telescope has a useful limit of magnification of about
45x-60x per inch of aperture, which is 140x-180x for the
ShortTube 80-A. Claims of higher power by some telescope
manufacturers are a misleading advertising gimmick and
should be dismissed. Keep in mind that at higher powers,
an image will always be dimmer and less sharp (this is a
fundamental law of optics). The steadiness of the air (the
“seeing”) can also limit how much magnification an image
can tolerate.
Always start viewing with your lowest-power (longest focal
length) eyepiece in the telescope. After you have located
and looked at the object with it, you can try switching to a
higher-power eyepiece, like the supplied 9mm Expanse eyepiece, to ferret out more detail. If the image you see is not
crisp and steady, reduce the magnification by switching to a
longer-focal-length eyepiece. As a general rule, a small but
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well-resolved image will show more detail and provide a more
enjoyable view than a dim and fuzzy, overmagnified image.
Photography with the ShortTube 80-A
With an optional camera adapter, the ShortTube 80-A
becomes a 400mm f/5 telephoto lens for a single-lens reflex
camera. For long-distance terrestrial or astronomical photography, you need only a T-ring for your particular camera
model. The T-ring attaches to your particular camera model
and threads onto the ShortTube’s focuser drawtube, coupling the camera body to the telescope (Figure 3).
Focus lock thumbscrew
Figure 3. The ShortTube 80-A with 35mm SLR camera
attached.
For closer-range (less than 1/4-mile) terrestrial photography,
you need both a T-ring for your camera and a T-adapter
(#5264), which provides the extra focus travel needed.
Remove the nosepiece from the camera adapter; the body
of the adapter will not be needed here. Connect the T-ring
to your camera body (remove any camera lenses first), and
connect the nosepiece of the camera adapter to the T-ring.
Now, insert the entire assembly into the focuser’s drawtube
(remove the eyepiece and diagonal), and secure with the
thumbscrew on the drawtube. Be sure to tighten the thumbscrew, or your camera could fall to the ground!
Use the camera’s viewfinder to frame the picture. Use the
telescope’s focuser to focus the image. Tighten the focus
lock thumbscrew on the telescope’s focuser to make sure
the camera does not slip out of focus.
You may want to consider using a remote shutter release
instead of the shutter release on the camera. Touching the
camera can vibrate the system and blur the resulting photographic image. Also, be sure to use a solid tripod.
Care & Maintenance
Give your telescope reasonable care and it will last a lifetime. Store it indoors or in a dry garage. Do not leave the
telescope outside except when using it. The optical tube is
aluminum and has a smooth painted surface that should
resist scratches and smudges. If a scratch does appear
on the tube, it will not harm the telescope. If you wish, you
can apply some white auto touch-up paint to the scratch.
Smudges on the tube can be wiped off with standard household cleaning fluid.
Any quality optical lens tissue and cleaning fluid specifically
designed for multi-coated optics can be used to clean the
telescope’s objective lens as well as the lenses of the eyepieces and finder scope. Never use regular glass cleaner or
cleaning fluid designed for eyeglasses. Before cleaning with
fluid and tissue, blow any loose particles off the lens with
a blower bulb or compressed air, or lightly brush the lens
with a soft camel hair brush. Apply some cleaning fluid to
a tissue, never directly on the optics. Wipe the lens gently
in a circular motion, then remove any excess fluid with a
fresh lens tissue. Oily fingerprints and smudges may be
removed using this method. Use caution; rubbing too hard
may scratch the lens! On larger lenses, clean only a small
area at a time, using a fresh lens tissue on each area. Never
reuse tissues.
Mounting provision:
Dovetail tube ring
mounting plate with
1⁄4"-20 threaded holes,
attaches to telescope
via tube rings
(included)
Finder scope:
8x Magnification, 40mm
aperture, achromatic,
crosshairs
Eyepieces:
20mm (20x) and 9mm
(44x) Expanse™,
1.25" barrel diameter,
multi-coated, threaded
for Orion filters
The ShortTube 80-A includes a soft-sided carrying case.
The carrying case will hold the ShortTube 80-A safely during transport and doubles as a convenient storage spot
when the telescope is not in use. You will need to remove
accessories such as the eyepiece, star diagonal, and finder
scope in order to place the telescope into the case. The
finder scope can be stored on top of the padded velcro flap
that covers the telescope. The other accessories can be
stored in the exterior pockets of the carrying case for easy
transport.
Star diagonal:
90° Mirror, 1.25" barrel
diameter
Case:
Deluxe soft case with
exterior pockets
Specifications
9947: ShortTube 80-A
Objective lens:
Achromatic doublet, airspaced
Objective lens coatings:
Fully multi-coated
Aperture:
80mm
Focal length:
400mm
Focal ratio:
f/5
Focuser:
Rack-and-pinion, 1.25",
accepts camera T-ring
Optical tube length:
15"
Weight of optical tube assembly:
3lbs. 7oz.
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One-Year Limited Warranty
The Orion ShortTube™ 80-A Refractor is warranted against defects in materials or workmanship for a period of one year from the date of purchase. This warranty is for the benefit of the
original retail purchaser only. During this warranty period Orion Telescopes & Binoculars will
repair or replace, at Orion’s option, any warranted instrument that proves to be defective, provided it is returned postage paid to: Orion Warranty Repair, 89 Hangar Way, Watsonville, CA
95076. Proof of purchase (such as a copy of the original receipt) is required.
This warranty does not apply if, in Orion’s judgment, the instrument has been abused, mishandled,
or modified, nor does it apply to normal wear and tear. This warranty gives you specific legal rights,
and you may also have other rights, which vary from state to state. For further warranty service
information, contact: Customer Service Department, Orion Telescopes & Binoculars, P. O. Box
1815, Santa Cruz, CA 95061; (800) 676-1343.
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